Rotary pump and motor



` H. H. MAcTAGGART AND H. G. SCOTT.l

ROT PU ND MOTOR.

APPLICA F Juv/24,1919.

' 1,360,128. Patented N0v.23,1

2 SHEETS-SHEET H. H. MAQTAGGART AND R. G. SCOTT. ROTARY PUMP ANO MOTOR.

'Y APPLlcAlOu Flu-:O 1.uLY24,1919. v 4

2 SHEETS--SHEET 2.

UNITEDV STATES PATENT OFFICE.

HUGH HOLMES MAGTAGGART AND ROBERT GRIGOR SCOTT, OF LOANHEAD, SCOTLAND,

ROTARY PUMP AND MOTOR.

speniiicanon of Letter'sraieni. Patented Nov, 23, 19211 Application led July 24, 1919. Serial No. 313,086.

To all whom t may concern:

Be it known that we, HUGH HoLMns MAG- TAGGART and ROBERT Gnieon SCOTT, subjects of the King of Great Britain and Ireland, and residing at Station Iron Works, Loanhead, Midlothian, Scotland, have invented Improvements in and Relating to Rotary Pumps and Motors, of which the Jfollowing' is a specification.

This invention has reference to improvements in and relating to rotary pumps and motors.

And in order that our invention and the manner of carrying the same into practice may be properly understood we have hereunto appended two sheets of explanatory drawings.

In these drawings Figures 1 to 5 each show diagrammatic views of halt` the e112 cumierence of the D tube around which the cylinder body carrying the radial cylinders rotates, so as to illustrate the various ways in which the hole apertures can be arranged in said tube to form the ports which communicate between the radial cylinders and the suction and discharge passages.

Fig. 6 is a transverse section of the D tube showing the arrangement of ports on the pressure and suction sides.

While Fig. 7 on` Sheet 2 is a transverse section corresponding to Fig. 6 with the cylinder body mounted axially thereon and carrying five sets of radial cylinders.

Referring to these drawings This invention has reference to improvements in and relating to pumps and motors of the rotary plunger type and particularly that class wherein aicylinder body 1 is driven by a prime mover and rotates about a stationary central spindle provided with passages and ports termed the D tube 2, the D tube constituting the valve of the pump; and wherein the pistons Il within the radially arranged cylinders 3 in cylinder body 1 derive their movement of reciprocation by coperation, without definite attachment, with an eccentrically adjustable stroke controlling ring or drum which revolves or iloats around in company with the cylinder body 1; a reversal of direction of the tluids motion being obtained by moving this eccentric ring from the one side to the other side of the axis of rotation.

Heretofore in applying this construction of pump in combination with the hydraulic or other gears, great noise or soun has resulted when the pumps aie at full pressure 'and speed, and the objective of the present invention is to obviate or silence these sound noises.

The usual practice has been to make the ports of the D tubes with' very little lap or lead, namely, when each cylinder Khas linished its suction or discharge stroke its piston is on the dead center, and the cover bridge between the suction and discharge ports of the D tube is practically the same width as the cylinder port. When the cylin der piston begins its discharge stroke the liquid in it at a low pressure is at once subjected to the full discharge pressure. At the end of the discharge stroke the high pressure liquid in each cylinder in turn cornes, Jfor the aforesaid reason, in sudden Contact with the low pressure liquid on the suction side port of the D tube. These sud den rises andfalls in pressure cause severe shocks and as there are usually 5 to 7 cylinders rotating` at a speed of 800 to 1000 revolutions per minute the resultant sound is very noisy.

Our improvements consist in arranging a series oli' hole apertures 5 in the D tube 2 to form the ports which communicate-between the radial cylinders 3 in cylinder body 2 and the suction and discharge passages, 7 and 8. These hole apertures 5 would preferably be formed of different or variable diameters or areas and shapes, as particularly shown in Figs. 1 to 5, and which has the effect of allowing the high pressure to come on the cylinder pistons on the discharge side S and oil on the suction side 7, gradually, thus reducing the shock. These holes 5, would be formed and arranged to suit various sizes and variable capacities of pumps,

as what suits one size may not be applicable to another.

In combination with the arrangement Jfor forming the ports as aforesaid, an additional improvement is obtained in some sizes of pumps by giving advance to the D'tube 2, as indicated at 9 Fig. 6. WVhenever the pistons 4 pass the horizontal line they commence their suction or discharge stroke, but as .the center line of the D tube 2 is advanced relative to said line as indicated at 9, this makes the cut-orf on the suction side and the opening to pressure a little vlate and. this again varies with the different sizes of pumps.

What we claim is :l

1. In rotary pumps andmotors the comvbination of a revoluble cylinder body formed with a series of radial cylinders and adapted to rotate on a fixed D tube and like valve, a series of hole apertures in said tube forming ports which communicate between the radial cylinders and the suction and discharge passages, so as to allow the high pressure to come oneach cylinder on the discharge side, and off on the suction side gradually and thus reduce shook and minimize sound, substantially as herein set forth.

2. In rotary pumps-and motors in combination, a revoluble cylinder body formed with a series of radial c linders and rotating on a fixed Dtube andy like valve, a series of hole apertures in said tube fornlingr ports which communicate between the radial oylin ders and the suction and discharge passages so as to allow the high pressure to come on each cylinder on the discharge side and off on 20 the suction side gradually and thus reduce shock and minimize sound, the D tube making the cut-off on the suction side and the opening to pressure a little late, substantially as herein set forth.

HUGH HOLMES MACTAGGART. ROBERT GRIGOR SCOTT. Witnesses:

EDWARD GIBB CLEMENT, STEWART Ross. 

